x86 processor compatibility

Discussion in 'Virtual PC' started by Ilya, Feb 1, 2004.

  1. Ilya

    Ilya Guest

    I have passed a thorough test suit to check how Virtual PC
    processor is compatible with an original one (Intel

    Whom I can write to discuss the results? I was in
    correspodence with Jon Garber a year ago, probably I can
    get his new e-mail?

    Thank you in advance!
    Ilya, Feb 1, 2004
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  2. IIya,

    Are you saying that your believe the CPU exposed to a virtual machine has
    some issues.
    If so please post a brief outline of these and details of the test suite and
    products used to perform your tests.
    Jon Garber is not listed as a Microsoft employee. In which group did you
    think he worked?

    Mike Brannigan [Microsoft]

    This posting is provided "AS IS" with no warranties, and confers no

    Please note I cannot respond to e-mailed questions, please use these
    Mike Brannigan [MSFT], Feb 1, 2004
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  3. Ilya

    Steve Jain Guest

    Jon Garber worked for Connectix.

    I am not aware of any issues with the P4 and Virtual PC.

    For clarifiication, there isn't a 'virtual pc processor', Virtual PC
    uses the host's CPU, it does not emulate the CPU. Only Virtual PC for
    Mac emulates a CPU, a P-II

    Steve Jain, Microsoft MVP for Virtual PC for Windows
    Website: http://www.essjae.com
    Steve Jain, Feb 1, 2004
  4. Ilya

    Ilya Guest

    I think it is true partially. Only application-level CPU
    commands are executed on the host CPU and only until they
    do not invoke any system-level actions like exceptions. It
    means that generally the results of all application
    commands are fully compatible with the host CPU, but all
    system-related behaviour has a lot of incompatibilites -
    even system protection does not always work well.
    Ilya, Feb 2, 2004
  5. Ilya

    Ilya Guest

    Mike, Steve,

    Thank you for the reply! Probably we could have a private
    e-mail correspondence? I am posting below some general

    Our company has created a proprietary test suit for IA32
    processor verification. It has about 200,000 tests, which
    cover all IA32 architecture by comparing it's behaviour on
    instruction level with a reference system, e.g. Intel
    Pentium-4. Each test sets required initial processor
    environment, executes a command or a set of commands,
    stores final processor environment (state) and compares it
    with a reference one. There is also more than a million
    tests for checking FPU calculations, which is not
    interesting in this case, because Virutal PC emulator uses
    host processor to execute these commands.

    I have passed some tests a year ago on Connectix product
    and a week ago on a Microsoft one. The last version still
    seems to have almost the same incompatibilites/bugs. I
    have not tried to classify them, but I think the rough
    number is not less than 50-100. For example the number of
    incompatibilites between Pentium-1 and P-4 or Athlon and P-
    4 is about 20-30. We could create a detailed report or
    provide you with the test suite, so you could considerably
    improve the product. That is what I would like to propose
    to discuss with you. Ilya
    Ilya, Feb 2, 2004
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